The present invention relates to a valve device for controlling the air intake for a compressor of a vehicle. The invention also relates to a compressor system including a valve device of this type, and also to a method for controlling an air intake for a compressor of a compressor system of a vehicle.
In modern vehicles, in particular commercial vehicles, systems operated with compressed air are often used. Systems of this type are found, for example, in brake systems and suspension systems. To generate and prepare the compressed air, compressed air preparation systems are used, which for example generate, filter and store compressed air and forward it onto the corresponding systems. Compressed air preparation systems of this type are used, for example, in lorries, rail vehicles and tractors and include a compressor and associated components of a compressor system in order to pressurize air. In order to achieve an efficient utilization of energy from a central drive device, such as an engine, turbochargers are often used in vehicles of this type. Energy can be drawn, for example, from an exhaust gas flow via a turbocharger. It is already known to use a turbocharger to precompress air before it is fed to the compressor of the compressed air preparation device or to the compressor system in order to increase the air volume flowing from the compressor per unit of time. In this context, it is known from document WO 2009/146866 A1 to supply air precompressed by a turbocharger or ambient air to the compressor, said air being fed to the compressor in a manner in which the turbocharger is bypassed.
The object of the present invention is to provide a possibility that is as reliable, simple and cost-effective as possible for selectively feeding ambient air or precompressed air to a compressor of a vehicle.
This and other objects are achieved in accordance with the invention by a valve device for controlling the air intake for a compressor of a vehicle, wherein the valve device comprises a valve housing, which comprises a first compressed air inlet for connection to an ambient air feed, a second compressed air inlet for connection to a charge air feed, via which precompressed air can be fed, and a compressed air outlet for connection to the compressor. The valve device has a first switched state, in which the compressed air outlet is fluidically connected to the first compressed inlet, and has a second switched state, in which the compressed air outlet is fluidically connected to the second compressed air inlet. The valve device further comprises a switching device, which is capable of switching the valve device between the first switched state and the second switched state. The valve device can thus be switched in a simple manner between an intake of ambient air and an intake of charge air to the compressor.
The valve device can be provided, in particular, for use in a compressor system of a vehicle. Besides two compressed air inlets, the valve device may, in particular, have only one outlet for connection to the compressor. The switching device or the valve device can be electrically or pneumatically actuated in order to switch between switched states. It is contemplated for a sensor device to be connectable or connected in the region of the compressed air outlet, in the compressed air outlet, or downstream of the compressed air outlet. In particular, the sensor device may include a pressure sensor and/or a flow sensor. It is expedient if the sensor device or its sensors are connected to an electronic control device. It is also contemplated to form or to consider the sensor device as part of the valve device and/or as part of a compressor system. The sensor device can be formed or connected to determine the switched state of the valve device and/or to detect and to transmit data for detection and/or control of the switched state.
The valve device may include an electronic control device and/or may be connected or connectable to an electronic control device. A control device of this type can be formed, in particular, to control and/or switch the valve device or the switching device between different switched states. The electronic control device of the valve device, for communication purposes, may be connected or connectable to at least one further, possibly superordinate, control device of the vehicle. In particular, the switching device can be formed for control by way of the control device. It is expedient if a sensor device, for signal transmission, is connected to a corresponding control device.
The valve device can be formed in such a way that, in each switched state, it provides a fluidic connection of its single outlet, specifically the compressed air outlet, to at least one of the compressed air inlets. In particular, it may be that the fluid line between the first compressed air inlet and the compressed air outlet and the fluid line between the second compressed air inlet and the compressed air outlet are not shut off simultaneously in any switched state of the valve device.
As a result of the switching device, a fluid line between the second compressed air inlet and the compressed air outlet can be closed in the first switched state and/or a fluid line between the first compressed air inlet and the compressed air outlet can be closed in the second switched state. In the first switched state, only compressed air is therefore forwarded via the first compressed air inlet to the compressed air outlet and ultimately to the compressor, whereas an intake of compressed air via the second compressed air inlet is prevented. Conversely, in the second switched state, only an intake of compressed air via the second compressed air inlet is possible.
The valve device may have at least one third switched state, in which the first compressed air inlet and the second compressed air inlet are fluidically connected to the compressed air outlet. Fed air can thus be mixed. If, for example, compressed air having a pressure critical for the compressor is fed via the charge air feed, the pressure can thus be lowered by an intake of ambient air or by releasing precompressed air via the first compressed air inlet. On the one hand, the compressor can thus be preserved. On the other hand, it is not necessary to intervene in the turbocharger system in order to reduce the charge air pressure, which reduces the circuit complexity for the vehicle.
In particular, the valve device may have a series of different switched states, in which the first compressed air inlet and the second compressed air inlet are fluidically connected to the compressed air outlet. The switched states may differ with regard to the cross-sections of the first compressed air inlet and of the second compressed air inlet released in the valve device and/or with regard to the ratio of the released cross-sections. Different mixing ratios can thus be adjusted. It may be expedient if the switched state of the valve device between the first switched state and the second switched state can be adjusted substantially continuously. The valve device may therefore have further intermediate switched states between the first switched state and the second switched state. Here, it may be expedient if a sensor for detecting the pressure level of the fed air is arranged in the ambient air feed and/or in the charge air feed. The sensors can be connected directly or indirectly via further electronic components to the electronic controller of the switching device or of the valve device. An electronic controller may be embodied in such a way that it sets a switched state of the valve device, in which air guided via the compressed air outlet to the compressor does not exceed a predetermined pressure threshold value. A control process of this type can be implemented, for example, based on the sensor signals and can be achieved by switching between switched states.
The switching device of the valve device may have a piston, which is movable between a first position corresponding to the first switched state, in which it releases a fluidic connection between the first compressed air inlet and the compressed air outlet, and a second position corresponding to the second switched state, in which it releases a fluidic connection between the second compressed air inlet and the compressed air outlet. The piston can be received within the valve housing, in particular in a channel for guiding the piston. It is contemplated for the piston to have a seal, which for example to provide a seal between the piston and the elements of the valve housing or of the valve device in which it moves, for example the channel. It is thus easy to switch in particular between the first switched state and the second switched state.
The valve housing may have a first valve seat, which is assigned to the first compressed air inlet, and a second valve seat, which is assigned to the second compressed air inlet. It may be possible to bring a piston of the switching device controllably into bearing contact with the first valve seat and controllably into bearing contact with the second valve seat. In the first switched state, the piston is in bearing contact with the second valve seat and closes the fluid line between the second compressed air inlet and the compressed air outlet. In the second switched state, the piston is in bearing contact with the first valve seat and closes the fluid line between the first compressed air inlet and the compressed air outlet. This construction provides an accurately defined movement space for the piston. In the region of at least one valve seat, a sensor, for example a contact sensor, may be provided for example for localization of the piston. Such a sensor can be connected to a control device. A valve seat can be formed, for example, as an opening assigning a constriction in a corresponding compressed air inlet or a line portion. In particular, the piston can be movable back and forth between a position in which it is in bearing contact with the first valve seat and a position in which it is in bearing contact with the second valve seat. Here, it is contemplated for intermediate switched states to be established.
The switching device may have a switching disk, which is rotatable between a first position corresponding to the first switched state, in which it releases a fluidic connection between the first compressed air inlet and the compressed air outlet, and a second position corresponding to the second switched state, in which it releases a fluidic connection between the second compressed air inlet and the compressed air outlet. This is a further possibility for providing a reliable switching device that is to be switched easily.
In a further development, the switching device also includes an outlet disk with an outlet opening, via which a fluidic connection from the switching disk to the compressed air outlet can be produced or established, and also an inlet disk with a first inlet opening, via which a fluidic connection from the first compressed air inlet to the switching disk can be produced or established, and with a second inlet opening, via which a fluidic connection from the second compressed air inlet to the switching disk can be produced or established. The switching disk is arranged rotatably between the outlet disk and the inlet disk and forms a switching opening. Furthermore, the switching disk may be rotatable between a first position, in which a fluidic connection exists between the outlet opening and the first inlet opening via the switching opening in the switching disk, and a second position, in which a fluidic connection exists between the outlet opening and the second inlet opening via the switching opening. A simple switching device can thus be produced, with which the rotation of the switching disk is hardly stressed by compressed air from one of the compressed air inlets, since the switching disk is rotatable orthogonal to the airflow. The first position corresponds to the first switched position, and the second position corresponds to the second switched position. The switching disk may cover the second inlet opening in the first position and may cover the first inlet opening in the second position in such a way that it shuts off a fluid line through the corresponding openings. In this variant also, intermediate switched states are of course possible, in which a defined mixing of compressed air fed from both compressed air inlets is possible, as mentioned above. The outlet disk and/or the inlet disk can be mounted within the valve housing such that they are stationary with respect to the housing.
It is contemplated for the switching device to include an electric motor as an actuation device for switching between switched states. The switching device may also be connected to a separate actuation device, such as a motor of this type. An electromagnet and/or a spring device can also be used as an actuation device. The actuation device can be actuated by one of the above-described control devices.
The valve device can be formed in particular as a 3/2 valve. No unnecessary inlets and outlets are thus provided, which facilitates construction and control.
The present invention also relates to a compressor system comprising a valve device for controlling an air intake for a compressor as described above. Depending on the design of the valve device, advantages substantially identical to those already discussed are provided for the compressor system. The compressor system may include an ambient air feed and a charge air feed.
The compressor system may include a shut-off valve, which is connected between the compressed air outlet of the valve device and the compressor, and which is capable of shutting off or releasing the intake of compressed air from the valve device to the compressor. In particular, the shut-off valve may be capable of shutting off an intake of compressed air between the compressed air outlet and the compressor in a shut-off position and of enabling an intake of compressed air between the compressed air outlet and the compressor in a conducting position. An undesired intake of compressed air to the compressor can thus be prevented in a simple manner, for example when the compressor is operated in an idle phase. The compressor may alternatively or additionally also be coupled to a compressor coupling, via which it can be uncoupled from a drive.
The compressor system may expediently include an electronic control device, which is suitable for controlling the valve device. The control device can be connected directly to the valve device or to the switching device. It is contemplated for the control device of the compressor system to be connected to a control device of the valve device. The compressor system may include a sensor device connected between the compressed air outlet of the valve device and the compressor. The sensor device may in particular comprise a pressure sensor and/or a flow sensor. The sensor device or its sensors can be connected to an electronic control device. It is contemplated for the sensor device to be formed or connected to determine the switched state of the valve device and/or, for detection and/or control of the switched state, to detect data and to transmit the data to a control device, which may be a control device of the compressor system and/or part of an on-board electronic system. A control device of this type may, in particular, be formed to control and/or switch the valve device or the switching device between different switched states. It is expedient if the sensor device, for signal transmission, is connected to a corresponding control device. The control device may be connected to a CAN bus of the vehicle.
The invention also relates to a method for controlling an air intake for a compressor of a compressor system, as is described herein, wherein, for the air intake, the compressor is connected to the compressed air outlet of the valve device. The method includes the following step of controlling the valve device in such a way that the valve device switches between two switched states. The control can be implemented based on sensor signals of the sensor devices or sensors described herein. During the control process, vehicle parameters such as the vehicle speed, engine parameters such as the engine speed, and/or compressor parameters such as the compressor speed can be taken into consideration.
In accordance with a further development, the valve device is controlled such that it switches between the first switched state and the second switched state.
The valve device may also be controlled such that it is switched to or from a third switched state, in which the first compressed air inlet and the second compressed air inlet are fluidically connected to the compressed air outlet.
Within the scope of this description, a vehicle may be any type of motor vehicle. In particular, a vehicle may be a commercial vehicle, a mobile construction machine, a rail vehicle, a tractor or a lorry. A compressor system may comprise a compressor. A compressor or a compressor system may comprise a compressor coupling. A compressor system may comprise components for compressed air intake, lines, valves, compressed air connections and/or similar components. Components for controlling compressed airflows, for controlling the compressor or a compressor coupling may also be considered as parts of a compressor system. A compressed air preparation device comprising an air drier, a multi-circuit protection valve and further components can be considered a compressor system or may comprise a compressor system. A control process can be carried out electronically, electrically or pneumatically. A combination of electronic and pneumatic control may also be provided. A compressor system may, in particular, comprise one or more electronic control devices.
An electronic control device may be provided for example to control the compressor and/or the compressor coupling and/or a valve device, in particular to control one of the above-described valve devices, and/or may be accordingly connected. A control device may carry out a control process based on signals from one or more pressure sensors. It is particularly expedient if the control process is carried out based on signals transmitted from the sensor device arranged downstream of the valve device and/or is based on signals from the charge air feed and/or the ambient air feed. A control process may be carried out under consideration of vehicle parameters such as a vehicle speed, engine parameters such as an engine speed, and/or compressor parameters such as a compressor speed. Here, it may be expedient to transmit corresponding parameters via an on-board electronic system, for example a CAN bus, to the control device, which carries out the control process.
A charge air feed is used for the intake of precompressed air for a compressor. The air can be precompressed by a turbocharger or by another suitable device. An ambient air feed is used for the intake of ambient air, which is not precompressed. The ambient air may therefore be at atmospheric pressure. The shut-off of a fluid line can be interpreted as the closing of any direct or indirect fluidic connection. Two components, between which a fluid line is shut off, expediently cannot exchange any fluid, in particular any compressed air. A fluid, in particular air or compressed air, can flow between fluidically connected devices, such as a compressed air inlet and a compressed air outlet.
One or more openings and/or line portions and/or pressure chambers can be assigned to a compressed air inlet or compressed air outlet of a valve housing. An inlet or outlet can therefore be understood as an inlet region or outlet region, provided compressed air flows in substantially just at one opening point and flows out again from the region substantially only at one opening point.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.